Scrape off some gunk and get a casting number and plug that into a search engine. If it’s Automotive, it’s pretty early by the small size. Like 1930s or earlier?
There were waaay fewer transmission builders than there were car and truck manufacturers. Should come up in the online search.
Yep. one lever shifts , the other selects. in released position the long lever gets you second and third, Hold the lever with the spring back and you get reverse and first. Maybe a little awkward but it works.